The present invention relates to the field of support structures and, more particularly, to support structures and methods which can support large sized and rotatable objects.
Support structures such as frames and other support devices have been used over the years for checking, testing, manufacturing, curing, winding, repairing, and performing many other functions on large sized objects such as portions of power generators or power generation systems. For example, U.S. Pat. No. 4,452,558 by Muraguchi titled A Support Structure For Checking And Repairing Heavy Rotatable Objects discloses a system which has a pair of spaced-apart roll support bases that each rotatably supports one end of a rotatable object. Each roll support base has a pair of rolls which are supported on an adjustable surface plate of a base frame by a spherical support mechanism. Due to the spherical support mechanism, the rolls on the support bases can uniformly support both ends of a cylindrical shaft extending through the rotatable object without imparting any thrust to the rolls even when horizontal leveling is not achieved. Because the rotatable object has a cylindrical shaft extending therethrough, the outer surface of the shaft smoothly rotates along the support rolls and the weight of the object is carried by the shaft. Many objects, however, do not have a centrally located shaft for rotation and carrying of weight.
Accordingly, with some large sized objects, a support shaft does not form part of the object and is neither practical nor feasible. For example, as shown in the prior art FIG. 1, a stator core 10 of a power generation system does not conventionally have a centrally located support shaft and yet often still needs to be rotated for winding, testing, curing, or other functions such as during manufacturing processes. The stator core 10 has a substantially cylindrical core body 12 and can be turned on rollers 17 to facilitate winding and resin drainage such as during an oven cure cycle. The core body 12 has a plurality of plate punching members 13 aligned along the core body 12. These current systems often have an inner frame, hydrogen frame i.e. frame through which hydrogen cooling gas flows or rings 15 permanently attached to the stator core 10 that are used as tools to be positioned against spaced-apart rollers 17 of a manufacturing frame 16 to allow rolling to occur without damage to the stator core 10. In many applications, however, these inner frames or rings are not required for any reason other than rolling. This can increase costs associated with construction and can increase the amount of time required for manufacturing or testing such objects.
With the foregoing in mind, the present invention advantageously provides in combination a stator core and manufacturing frame that reduces costs and time associated with manufacturing or testing stator cores, and reduces the risk of significant damage during rolling of the stator cores. The present invention also advantageously provides stator core plate punching members and methods of rolling a core body that allow rollers of a manufacturing frame to roll thereagainst without risk of significant damage to the stator core such as during winding or oven curing cycle operations. The present invention additionally provides a stator core and manufacturing frame combination that can reduce or minimize axial reaction load from rolling the stator core and thereby reduce or minimize the structure needed to support the load.
More particularly, the present invention provides a combination stator core for an electrical machine and a stator core manufacturing frame. The combination preferably has a stator core having a substantially cylindrical and elongate core body. The core body preferably includes a plurality of punching members. Each of the punching members has a substantially annular plate body member having a smooth outer surface. A manufacturing frame is preferably positioned to substantially underlie the core body of the stator core. The frame preferably includes a plurality of spaced-apart rollers each positioned to contact the substantially smooth outer surface of each of the plurality of plate punching members of the core body when positioned to roll thereagainst during rolling of the stator core so that rolling occurs with less risk of damage to the stator core. If any variations in the substantially smooth outer surface of the plate punching members occurs, then these variations are preferably slight and smooth as well.
The present invention also provides a plate punching member for a stator core of a power generator. The plate punching member preferably comprises a substantially annular plate body member having a substantially smooth and uniformly arcuate outer surface. A plurality of these plate body members may be aligned in side-by-side relation with one another to form at least portions of a stator core. When a plurality of the plate body members are aligned to form a stator core, a roller of a frame contacting the outer surface of each of the plate body members is able to roll substantially smoothly along the outer surfaces without risk of significant damage to the stator core. The plate punching member also preferably has a substantially circular opening formed in a medial portion of its plate body member, the substantially circular opening extending therethrough. A plurality of slots is formed in the plate body member. Each of the plurality of slots preferably has a slot open end and a slot bottom. Each of the plurality of slots preferably extends outwardly in a radial direction from the slot open end closely adjacent the opening formed in the medial portion of the plate body member toward the slot bottom spaced-apart from the outer surface.
The present invention additionally provides a method of rolling a substantially cylindrical core body while lessening the risk of significant damage to the core body. The method preferably includes positioning a plurality of rollers of a frame to contact portions of outer surfaces of a plurality of plate punching members of a substantially cylindrical core body and rotating the core body in either a clockwise or counterclockwise direction about an axis longitudinally extending through the core body without significant risk of damage to the core body.
Accordingly, the present invention allows rolling directly on the outside diameter of the core body and eliminates the need for an inner frame, hydrogen frame, or rings to roll the core. By contrast, these additional frames or rings, according to the prior art, were often permanently attached to the core body or used as tools. Thus, their elimination according to the present invention can save construction costs and time, and yet the core body is still not likely to be damaged during rolling. By providing a more consistently cylindrical shape for the core body according to the present invention, frictional forces that otherwise would tend to screw the core body axially with respect to the rollers are reduced. When the plurality of rollers extend along the sides of the core body and are aligned together, the axial reaction load from rolling can be significantly reduced or minimized to thereby reduce or minimize the necessary support structure needed to support the load.